Indestructawool durability technology is intentionally knit into high impact wear zones, helping your socks outlast your longest adventures. 4 Degree Elite Fit System offers a performance fit with strategic stretch and mesh zones to promote breathability while helping protect against blisters. Virtually Seamless toe technology is a flat knit toe seam designed for additional comfort. Women's specific fit features a narrower heel shape designed for secure, all-day comfort. Achilles tab prevents sock from slipping into footwear.